Substance and process of using the same for refrigerating purposes



Patented Sept. 20, 1927.

UNITED STATES 1,642,943 PATENT OFFICE.

WILLIS H. CARRIER, OF ESSEX FELLS, NEW JERSEY, ASSIGNOR '10 CARRIER ENGI .NEERING CORPORATION, OF NEWARK, NEW JERSEY.

. SUBSTANCE AND PROCESS OF USING THE SAME F OR REFRIGERATING .PURPOSES. I

No Drawing.

My invention relates to a substance and a process of'using the same-in refrigeration, whether for making ice, for cold storage work, for cooling water for use. in conditioning air, or for other cooling purposes.

The substance known as dichloroethylene and having the formula C, H 01 has certain properties or characteristics which are ideal in a refrigerating medium. It has a boiling point of approximately (1.; it is inactive towards common metals at any temperature, either in the liquid or gaseous state, or in the presence of water; it does not volatilize appreciably at ordinariy atmospheric temperatures; it will not reeze at any temperature which will be encountered. The gas is dense, being several times heavier than air and does not readily diffuse or spread, thus permitting the refrigerating apparatus to be opened up at any time without removing the liquid and without objection from fumes; the liquid will not explode or readily burn and it can be handled like water in open containers with entire safety.

I have found, however, that the commercial dichloroethylene, which has been used for refrigeration, has the objection that its boiling point is variable. The boiling point increases as the lirf pid is evaporated so that purging in the re igerant and constant reduction of volume of the liquid causes a continually rising boiling point, and alsocauses an appreciable difference between the boiling point and the condensing point, thereby reducing the efiiciency of the refrigerating machine. The reason for this is that normal commercial dichloroethylene contains two isomers; one, trans-isomer,

having a boiling point of approximately 49 (1., and the other, cis-isomer, having a boiling point of approximately C. The proportlon of these isomers is approximate- 1y 25 percent or 30 percent trans-isomer to 7 5 percent or 70 percent cis-isomer. There'- spective vapor pressures of these two isomers at the'same temperature is about in the proportion of 1 to .54, thus in a normal mixture of the saturated vapors of the different isomers, about percent will be of a trans-isomer and 35 percent will be of a cis-isomer.

ThlS ob ect1on I havesucceeded 1n overcoming by separating thetwo isomers of the commercial dichloroethylene, which Application filed March 22, 1924. Serial No. 761,230.

may be done, for example, by fractional distillation, and by using either of the two somers 'as a refrigerant. Either of the isomers, when comparatively free of theother isomer, has a range of boiling points purposes, regardless of the quantity evaporated. While either of the two isomers may be used as a refrigerant, it has been found less difficult to prepare the 'cis-isomer, which has the higher boiling point, this isomer being present in greater quantities in the commercial dichloroethylene.

In my process of refrigeration, using this new refrlgerating medium, the refrigerant abstracted from the water or other medium or enclosure being cooled, and the refrigerant vapor is compressed and condensed, the liquefied and cooled refrigerant being returned to be again evaporated, this cycle of operations being continuous. Preferably, a centrifugal-compressor is used which produces only a moderate difference in pressure, and the refrigerant is condensed as well as evaporated at a pressure below one atmosphere so that the entire system is under a; partial vacuum 'All liquefied a'efrigerant is immediately. transferred asformed from the condenser to the evaporator, and any surplus, liquid is maintained in the evaporator. Simultaneously with the return of the liquefied refrigerant from the condenser, the residual" dense refrigerant vapor,- together with any non-condensible gas or air that may be present are witharate it from the non-condensible gas, the condensate is returned to the evaporator at the temperature level of the evaporator. This enables the boiling point in the evaporator and theiicondensing point in the condenser to be maintained more nearly the same, since if the liquid is allowed to colwhich is sufiiciently stable for commercial liquid is evaporated, preferably by the heat drawn from the condenser, and after compressing and condensing the vapor to seplect in the condenser, there would be an ac- 1 cumulation of the less volatile portion in p the condenser while the more volatile portion would be removed.

I claim as my invention: I

1. A refrigerating process which comprises evaporating a refrigerant consisting substantially of only one of the isomers of dichloroethylene, compressing and condensing the resultant vapor to liquefy the-same ingthe resultant vapor to liquefy the same and returning the liquefied refrigerating medium to be again vaporized.

3. A process of refrigeration which comprises evaporating, compressing and condensing a refrigeratin medium having one only of the isomers o dichloroethylene under a pressure at all times not materially greater than one atmosphere.

4. A process of refrigeration which comrises evaporating, compressing and conensing a refrigeratingmedium having one only of the isomers, of dichloroethylene all I in a artial vacuum.

5. process of refrigeration which comprises evaporating, compressing by centrifugal action, and then condensing a refrigerating medium having one only of the isomers of dichloroethylene under a pressure at all times not materially greater than one atmosphere.

6. A process of refrigeration which comprises evaporating, compressing by centrifugal action, and condensing a refrigerating medium having one only of the isomers of dichloroethylene all in a partial vacuum.

7. The process of refrigeration which comprises evaporating a refrigerating medium, aving one only of the somers of dichloroethylene at a pressure below atmosheric pressure, compressing the vapor. thus ormed, and condensing the compressed vapor at a pressure "not materially greater than approximately atmospheric pressure.

8. A refrigerating device, comprising an evaporator, a compressor and a condenser connected together in aclosed circulatory system, and a uantity of one onl of the isomers of die oroethylene in sai system, the pressure in said evaporator being less than atmospheric pressure.

9. A refrigerating device comprising an evaporator, a compressor and a condenser connected together in a closed circulatory system, and a quantity of one only of the isomers of dichloroetnylene in said system, the pressure in said evaporator being less than atmospheric pressure, and pressure in said condenser not materially greater than approximately atmospheric pressure.

10. A refrigerating device comprising an evaporator, a compressor and a condenser connected together in a closed circulatory system, and .a isomers of die oroethylene in .said system, .the pressure in said evaporator being less than atmospheric pressure, and pressure in said? condenser bein less than atmospheric.

lBluantity of only one of the A refrigeratmg device having an evaporator, centrifugal compressor and con denser connected in a closed circulatory system, and a refrigerating medium having one only of the isomers of dichloroethylene as the refri erating medium.

12. A refrigerating device including an evaporator, centrifugal compressor and condenser connected in a closed circulatory system and containing therein a. refrigerating medium having one onl of the isomers of dichloroethylene, the di erences in internal pressures between the compressor, 'condenser and evaporator being relatively small.

13. A process of refrigerationfwhich comprises evaporating, compressing by centrifugal action, and then condensing cis-isomers of dichloroethylene under a pressure at all times not materially greater than one atmosphere.

14. A process of refrigeration which comprises evaporating,compressing by centrifu al action, and condensing cls-isomers of dichlorocthylene all in a partial vacuum.

15. A process of refrigeration which comprises evaporating, compressing and conensing cis-isomers of dichloroethylene under a pressure at all times not materially greater than one atmosphere.

16. A process of refrigeration which comprises evaporating, compressing and conensmg ole-isomers of dichloroethylene all in a partial vacuum.

17. The. process of refri eration which comprises evaporating a refrigerating medium having the ois-isomers only of dichloroethylene at a pressure below atmospheric pressure, compressing the vapor thus formed, and condensing the compressed vapor at a pressure not materially greater than approximately atmospheric pressure.

18. A refrigerating device, comprising an evaporator, a compressor and a condenser connected together in a closed circulatory system, and a uantity'of cis-isomers of dichloroethylene 1n said system, the pressure in said evaporator being less than atmospheric ressure.

19. refrigerating device, comprising an evaporator, a compressor and a condenser connected together in a closed circulatory system, and a uantity of cis-isomers of dichloroethylene in said system, the pressure in said evaporator being less than atmospheric pressure, and pressure in said conenser not materially greater than approximately atmospheric pressure.

20. A refrigerating device comprising an evaporator, a compressor and a condenser connected together in a closed circulatory system, and a quantity of cis-isomers of dichloroethylene in said system, the pressure in said evaporator being less'than atmospheric pressure, and the pressure in said condenser being less than atmospheric.

21. A refrigerating device having an evaporator, centrifu l compressor and condenser connecte in series, and cis-isomers 3r dichloroethylene as the refrigerating me- 5 22. A refrigerating device including an evaporator, centrifugal compressor and condenser connected in a closed circulatory system, and containing therein cis-isomers of dichloroeth lene as the refrigerating medium, the difiirences in internal pressures 10 between the compressor, condenser and evaporator being relatively small.

WILLIS H. CARRIER. 

